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thus converting UNITED STATES PATENT (")FFICEH COULTER W. JONES, 0F MIDLAND, MICHIGAN, ASSIGNOR TO THE DOW CHEMICAL COMPANY, OF MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN.

MANUFACTURE or BROMATES.

No Drawing.

To all whom it may concern:

Be it known that I, CoUL'rER W. Jones, a citizen of the United States, and a resident of Midland, county of Midland, and State of Michigan, have invented a new. and useful Improvement in the Manufacture of Bromates, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The present invention, while relating primarily to the transposition of various bromates by converting the same first to barium bromate and then to a bromate of the desired metal, has more particularly as its object to effect a more complete separation and recov' cry of various bromates from other salts by the bromate in such mixture to barium broma'te, separating the latter from the mixture and then converting it either into the original or other desired bro- Inate. My improved process is applicable to the trans msition of hromates more soluble than barium bromate to barium bromate, which may then he converted into the bromate of any metal Whose carbonate or other salt forms a less soluble compound with barium than with the reacting metal.

To the accomplishment of the foregoing and related objects the invention then coir sists of the steps hereinafter fully described and particularly pointed out in the'claims, the following; description setting: forth in do tail certain steps emlmdying, the invention, such described steps constituting, however, but one of various ways in which the prin- (iple of the invention may he used.

The conversion of the original bronull'c into barium broiuatc is efl'i-vlcd by adding barium broinid there-to, inc reaction being represeutml by the following equation The further conversion of the barium bro mate which is thereupon precipitated into the bromate of a desired metal, is effected by adding the carbonate oi such metal, where upon the alleging reaction will occur, as-

Specifieation of Letters Patent Patented June 22, 1920. Application filed June 25, 1918v Serial No. 241,747.

suming sodium carbonate to be added in order to produce sodium bromate The barium carbonate resulting from the reconversion of the barium bromate into broinate of other desired metal may be again converted into barium bromid for use over a grain in the first step of the process, this bein; arromplishcd by the use of hydrohromic acid as represented by the following equation 2- or the barium carbonate may he treated with iron bromid, givinr the following reaction Pra tically all bromates except silver, n'iercury, and those oi some raremetals, are more soluble than barium bromate, which is soluble only to about 0.3% at Zero degrees and 5.6% at 10!) dogs. In carrying out the process accordingly a hot conccnrated solution is preferably made of the original broinate to be converted or transposed and thr barium bromid thereupon slowly added with stirring until the reaction is completed, and addilionul solid broinafe may he added lo this reacting solution in order in securimaximum concentration of reuniting broiualisolution. The solution is then allowed to cool with the result that the barium hromal pra tically all precipitates out, whereupon it may be separated in any approved 'lashii'm.

In the second step the bariun bromate thus separated out is placed in a container, water added and the mixture heated, Where upon a solution of sodium carbonate, for ex ample, is added until the reaction is com- )lete. The resulting solution of sodium liromate is then filtered from the precipitate of barium carbonate.

An important use of the process is in ctfecting a more complete separation and recovery of bromatcs mixed with bromids and other salts, as for example, to effect a more complete recovery of sodium bromate from liquors containing sodium bromid and HU- dium bromate, such as are obtained in the manufacture of bromids. The best fractional crystallizatio 'i of this n'iixture leaves a liquor containing the salts in the ratio of about 93% sodium bromid to 7% of sodium bromate, but a nearly complete recovery of these salts can be obtained from such rt sidual liquor by the use of the present. process.

other modes of applyin; the principle if my invention may be employed instead oi the one explained, changibeing: made as re gards the method herein disclosed. provided the step or steps stated by any of the following; claims or the mplivah-nt of Sui-h stated step or steps be employed.

1 therefore particularly point out and dis tinctly claim as my invention 1. In a method of recovering a soluble bromate from admixture with other salts, the steps which consist in converting such bromate into relatively insoluble bariumbromate; and then separating out such barium broniate, substantially as described.

2. In a method of Recovering a soluble bromate from admixture with other salts, the steps Which consist in converting such broniate into relatively insoluble barium bromate; separating out such barium bio mate; and then converting the same to uch original, or other bromide. as desired.

2%. In a method of recovering a soluble broinate from admixture with other salts, the steps which consist in adding barium bromid to a. solution of such bromatc, where by the latter is converted into relatively in soluble barium bromatc; separating out such barium bromate; and then converting the same to such original, or other hromatc, as desired.

4. In a method of recovering a soluble broinate from admixture with other salts,

the steps which consist in adding barium bromld to a hot, concentrated solution of such bromate. whereby the latter is converted into relatively insoluble barium bromate; cooling the solution; separating out such barium bromate; and then converting the same to such original, or other bromate, as desired.

5. In a method of recovering a soluble bromate from admixture with other salts, the steps which consist in adding barium broinid, with stirring, to a hot, concentrated solution of such brornat/e, whereby the latter is converted into relatively insoluble barium bromate; cooling the sobjltion; separating such barium hromate; and then addin the same to a solution of the carbonate 0 the metal of whichthe bromate is desired.

6. In. a method of recovering a soluble bromate from admixture with other salts, the steps which consist in adding barium bromid to a solution of such bromate, Whereby the latter is converted into relatively insoluble barium bromate; separating out such barium brornate; reacting between the same and the carboiiate of the metal of which the broniate is desired; and converting the barium carbonate thus l'ormcd into broniid For use again in the first step.

T. In a method of recovering a soluble broznate from admixture with other salts, the steps which consist in adding barium bromid to a solution of such bromate, where by the latter is converted into relatively in soluble barium bromate; separating out such barium broniatc; reacting between the same and the carbonate of the metal of which the bromate is desired; and treating the barium carbonate thus formed with iron bromid, \vhereby barium bromid is formed for use again in the first step.

ta. The method of recovering a soluble bromate from admixed bromid, which coir sists in converting such bromate into relatively insoluble barium bromate; separating out such barium bromute; and then reconvcrtinp the same to such original bromate.

H. The method of recovering an alkali metal bromate from admixed bromid, which consists in adding barium bromid to a hot concentrated solution of such bI'OlIlHbG and bromid, whereby such bromate is converted into relatively insoluble barium bromate; cooling the solution; separating out suchbarium hroniate; and then adding the same to a solution of the carbonate of such alkali metal. 1

Signed by me, this 20th day of June, 1918.

COULTER \V. JONES. 

